Microsoft announced that it will issue a n emergency path for its Internet Explorer browser that will close up a security hole hackers used to exploit a number of US technology companies.

The vulnerabilities came to light as hackers last week launched a sophisticated cyber-attack against a number of Silicon Valley technology companies, including Google.

To date, the only successful attacks that security experts are aware of revolve around Microsoft's older browser, Internet Explorer 6. 

We continue to recommend customers update to Internet Explorer 8 to benefit from the improved security protection it offers, said George Stathakopoulos, Microsoft's general manager trustworthy computing security.

Google said last week it was thinking about quitting China after a attackers infiltrated its network, resulting in theft of its intellectual property.

On Thursday, McAfee disclosed that Google and some 30 other companies were targeted by a spear phishing campaign, dubbed Operation Aurora.

Attackers tricked employees of the companies to click on a phony link. If they were using the specific version of the browser, they would have been compromised.

The exact time of the patch's release, as well as the scope of users who should install it, will be revealed tomorrow.